A telescope dream for any budget

Posted By Pamela on Jul 26, 2007 | 10 comments

As a graduate student at the University of Texas, I got to accompany the undergraduates on star parties (nominally as the ‘responsible’ adult, but really as a colleague in madness). We’d load up our cars with every telescope we could find, about a dozen pair of binoculars, and laptops with planetarium software. We’d get pizza on our way out to the old missile silo that served as our observing platform (only in Texas…), and stay out until clouds or cold forced us indoors. All the scopes would get setup, and we’d usually cluster in small groups, working in teams of two or three to find faint fuzzies. There were about 10 people in the core club, students who’d always be there, always observing. An additional couple dozen students might float in and out on a perfect night as people worked to get their observing credits for their astronomy classes. It was fun. It was hands on. It was us versus the sky. It is one of my favorite memories of grad school.

It is widely recognized that people learn better when they are able to participate in activities related to what they are learning. These gains are further increased when learners can participate in real research experiences. In astronomy, there are two basic paths to get into research: data-mining and telescopic observations. While data mining is a powerful and often free research tool, it is hard to get excited about downloading images (or just numbers in some cases) from a database to analyze. There is a certain romanticism inherent getting out under the stars that can turn a classroom assignment into a lifetime hobby. Making these experiences possible requires an investment in a telescopic system. At Texas we had plenty of scopes. Here, we don’t. People keep asking me, if you could get anything, what would you get? This entry is my attempt to answer that question.

Telescopes aren’t cheap, but large optics aren’t required to make real contributions to science. New telescopes aren’t required either (but clean telescopes are – but hey, that’s what student labor is for). This summer, as I’ve done star parties with one telescope and too many people, I’ve given a lot of thought to what I’d buy if I had the budge. In general, I’m assuming that on any given night there is the potential for about 20-30 people to show up, and that a class forced to observe will have lab sections of 24 students. Within that odd parameter space, here is what I’d buy. (Images thieved from Oceanside Photo & Telescope. They’ve been good to me, and I’m going to give them an unasked for recommendation as I steal their telescope images 🙂

Strictly Visual Observing, Starter Packages
My favorite way to teach astronomy is with lots of strictly visual equipment around. Yes – one needs a CCD and expensive computerized scope to do anything complex, but the heart of astronomy is located in the eye. In a low budget, small class / small club environment, I don’t advocate spending limited resources on computerized anything – Get equipment students can pickup, take on a club camping trip some where dark, and use on their own without your help! Here are two combinations for two small budgets that will get as many eyes on the sky as possible. In both cases, kids can work in groups finding objects with binoculars and estimating magnitudes, and take turns using the telescope.

A 6″ Dobsonian is easy to transport, easy to setup, and easy for anyone age 12 and up to use. This simple telescope will form a good foundation to a beginning program. The SkyQuest IntelliScope has a simple computer system that will allow give users digital arrows to point the user toward celestial objects. 6″ is sufficient to allow the Andromeda galaxy to be seen from cities as large as Boston, MA.

Schmidt-Cassegrain Telescopes (SCTs) and Maksutov-Cassegrain Telescopes (MCTs) are reflecting telescopes that can be affordably mass-produced. They offer relatively abberation free large fields of view. The geometry of the scope makes it easy to mount cameras to these telescopes using standard T-Rings. These telescopes, however, are heavy, harder to setup then Dobsonian telescopes, and require practice to use well. An 8″ telescope can resolve individual stars in many open star clusters, and in dark locations can allow structure to be seen in the Andromeda galaxy and nebula listed in the Messier catalogue.

Beginning CCD + Visual Observing
One of the problems with astronomy is that you can’t turn back time and repeat an observation. If there is a question regarding observations the only way to double-check results is to take images and re analyze the images. The best way to take images is with a CCD digital camera. The best cameras for science are black and white and do not have anti-blooming sensors. These cameras require a simple computer with a large hard drive, and in this instance it is best to construct a permanent telescope mount (such as a cement pillar), and invest in software good software for the classroom, such as Mira AL. It also becomes necessary to invest in a good finding scope and filters when using a CCD. Filters allow data from different systems to be systematically compared. With out filters, only timing data can be combined accurately.

Unfortunately, CCD observing is boring. To keep the thrill of astronomy alive, many observers take visual observations of bright objects while their CCDs plug away on autopilot. This technique is excellent for the classroom; students can occupy themselves with visual observing while waiting for their turn operating the computer.

Building your Dream Observatory
If you have the budget, it is possible to built a professional observatory on an SUV sized budget. How you spend your money depends on what resources you have. The must have item is an excellent mount. A mount such as the “Paramount” (by Software Bisque, $12,500) can support many different types of telescopes and represents a good initial investment of dollars. DFM Engineering also makes superb mounts for a variety of sizes of telescopes. Once a good, permanently situated, mount is in place, the next major expenditure is an optical tube assembly. The majority of professional systems use Richey-Chretien Telescopes (RCT). This design is currently marketed by RC Optical Systems in a variety of sizes (a 20″ stars at $33,000). Beyond a mount and telescope, money should also be invested in a 4″ guide scope and a guide camera.

10 Comments

Very good information Pamela. I would also add that if people wanted to see any scopes in action before they plunked down their hard-earned bucks, they should hook up with their local astronomy club and attend a star party, meeting, etc. Some, like ours, have a big observatory as well.

As an astronomy club officer, i’d love to have a relationship with some nearby school offering astronomy courses. My club has an observatory with a 7 instruments and lots of eyepieces and filters. At most star parties, though, most members bring their own scopes and often don’t even open the dome or wheel out the 22″ dob! We could host a class of 30 with 2 students per scope, on average.

I totally agree that the xt6i is a very high price/performance instrument. You could also get one xt6i, a green laser on a mount, and a bunch more xt6’s (no computer).

There’s also a used market.

But the guys at the club do wide field narrow band CCD imaging with 80mm refractors and get incredible performance.

So far, this is totally outside my price range. I’m currently goofing around with what can be done with cheap cameras on a dob (since that what i have). I’ve got good shots of the Moon, anyway.

Thanks for the information. I’m looking for binoculars for me and my daughter. Can anybody compare the Nikon 10×50 recommended here with Celestron OptiView 10×50 LPR with “light pollution reduction” filter? About the same price, Celestron claims to work better in urban environments.

Thanks for information. But according to me it is not “Any Budget”. Can you suggest me how to make a telescope? I possess to 8″ pyrex disk and abrasives of different guages. Two mugs of turpine. One net bought from wilman bell Inc. Yes, one book is there of Jean texerao. But as I am a commerce graduate it is very nut to crack. Can you help me?

kvenlander

July 28, 2007

Kevin, thanks!

Prasanta, I think the best way to build your own is to find a group of people who are doing it. See if you can find active amateurs in your area. Or somebody who has made one – this is a skill not easily learned online. This is what I’m going to do – luckily there is a group of telescope builders close.

Steve

October 7, 2007

I like the fact that you give the binocular option. I was dead set on buying a telescope, until research led me to get a pair of binocs first. I bought a reletively cheap pair just to see what it was about. 16×50 porro prism BK7 for around 50 bucks. Now I am looking to upgrade, not to a telescope, but to a higher quality pair of astro binocs. I was happy with what I could see with the pair I have now, and it is so easy to use and portable with a mono-pod, I am not sure if I will ever actually get a telescope.

Could you do a piece on binoculars? What to look for, what to avoid, and what to expect.

Thanks Pamala, love you on Astonomy Cast!

M Hiltner

February 15, 2008

Great information. However, had anyone noticed the Moon pasted into the image is backwards?

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About Me

Dr Pamela L Gay is an astronomy, technologist, and creative focused on using new media to get people learning and doing science. All ideas and opinions stated on this website are entirely her own unless otherwise stated.